The present invention relates to a recording apparatus capable of writing characters with a writing pen and erasing written characters by means of an erasing pen which traces same.
Referring to FIG. 11(a), there is illustrated a character "A" which is written on a sheet of recording paper with a conventional pen-recording device. The operation of writing the character "A" is conducted by operating an alphabetic key indicative of "A" on a keyboard of the device. Upon operation of the key, a control means of the device retrieves a set of character pattern data corresponding to the character from a pattern memory, and according to the retrieved set of data causes a paper feeding means to rotate a platen along a line of feed, causes a carriage carrying a writing pen and an erasing pen to move perpendicularly to the line of feed, and causes the writing pen to contact with or release from the recording paper. After one character has been written, the control means causes the carriage to bring the writing pen into position for writing the next character.
On the other hand, in order to erase the written character "A", the carriage is first located opposite to the character "A" as a result of operating a space key, a backspace key and/or the like which generate signals commanding the carriage to move. Then, an erasing key is operated so as to generate a signal commanding an erasing operation. Consequently, the control means reads the set of pattern data corresponding to the character "A" out of the pattern memory, and based on the set of data effects the same operations as performed for the above-described writing operation of the character "A", so as to cause the erasing pen to trace the character.
However, such a conventional recording device has a problem that, unless the erasing pen traces the written character "A" with high accuracy, the character is not completely erased. For example, referring to FIG. 11(b), there is illustrated the character "A" as shown in FIG. 11(a) after being so traced with the erasing pen as indicated in two-dot chain line. The character "A" traced is not completely erased, because the erasing operation was conducted with the erasing pen out of position by a small distance to the left as viewed facing the figure. This problem with the conventional type recording device results from a positioning error of the erasing pen with respect to the written character. Even if the recording device is constructed with higher accuracy, the problem will remain.